Method and apparatus for producing low temperature high pressure liquid carbon dioxide



Jan. 9, 1934. F R ZUMBRO 1,943,232

METHOD AND APPARATUS FOR PRODUCING LOW TEMPERATURE HIGH PRESSURE LIQUID CARBON DIOXIDE Filed 001;. 15, '1928 gwuentoz Fez/ME 510M1 0 Patented Jan. 9, 1934 UNITED STATES OFFIC Frank R. Zumbro, Waynesboro, Pa., assignor to Frick Company, Waynesboro, Pa., 2. corporation of Pennsylvania Application October 15,

7 Claims.

This invention relates to method and apparatus for producing low temperature, high pressure liquid carbon dioxide.

An object of the invention is to provide a process and apparatus to be used in connection with a plant for the manufacture of solid carbon dioxide which is sometimes called dry ice." The machines which manufacture this product are sometimes called snow producing machines. The purpose of this invention is to supply liquid carbon dioxide to the snow machine and to supply this liquid under very high pressure, and yet at an extremely low temperature. In the snow machine the high pressure low temperature carbon dioxide is changed into the form of snow by a reduction in its pressure which allows it to quickly expand.

An object of the invention is to deliver cold high pressure liquid to a snow machine in the most economical manner.

Referring to the accompanying drawing, which is made a part hereof and on which similar reference characters indicate similar parts,

Figure 1 illustrates the general lay-out of the apparatus in which the method is preferably carried out, many of the elements of the system being shown diagrammatically.

Figure 2 is a section of an expansion valve.

In the drawing, numeral 10 indicates a supply line through which carbon dioxide from any suitable source is delivered to a first stage compressor system shown at 11 and 12. From the compressor the fluid passes through a pipe 13 into a cooler 14. This cooler consists of a shell or casing through which tubes are run, through which tubes cooling water from pipe 8 is circulated. The carbon dioxide occupies the spaces within the casing surrounding the cooling tubes.

The cool gas passes from the cooler 14 through a pipe 15 to a mixer unit, shown as a whole at 16. In this mixer the gas is mixed with suction gas from a second stage liquid cooler, shown at 1'7, and which will be more fully described. The mixer 16 is simply a shell in which the gases from the pipe 15 are mixed with such gases as enter the mixer through the pipe 18 from the liquid cooler 17. The mixing chamber 16 serves a dual purpose:-First, it aids in the removal of oil or water which may have been carried over from the first stage compressor;-Second, it aids in reducing the temperature of the gas from the first stage compressor which results in delivering the mixture at a cooler temperature to the inlet of the next compressor stage. The second stage compressor unit is shown as a whole at 1928. Serial No. 312,702

19. Gas from the mixing chamber 16 passes through the pipe 20 to the inlet of this compressor, where it is compressed and discharged through a pipe 21 to a cooling unit 22 similar to the cooling unit 14. From this cooling unit the cool gas passes through pipe 23 to a mixing chamber 24. In this chamber the gas is mixed with a cool gas which enters it through a pipe 25 from a first stage liquid cooling unit 26. From the mixing chamber 24 the gas passes through a pipe 2'7 into a heat exchange unit 28 from which unit it passes through a pipe 29 to a third compressor 30. The heat exchange unit 28 consists of a shell in which tubes or coils are placed and through which coil, suction gas at low temperature from the snow machine passes coming from the snow machine through pipe 31. This cold suction gas takes up additional heat from the gas which passes to the third stage compressor. The gas from the suction line 31 which passes through the heat exchange unit passes then to the suction line 10, where it is drawn into the first stage compressor. From the third stage compressor 30 gas passes through a pipe 32 to an oil separating unit 33 which is also a cooling unit similar in structure to cooling units 14 and 22. This cooling unit as stated is similar to those previously described, and consists of an outer shell 34 with cooling'water pipes 35 extending throughout. Cold water from fluid line 9 is circulated through the coils. As the gas passes around the cooling coils it is cooled, and at the same time such oil as is contained'in the gas is deposited on the cold surfaces of the tubes, from which it drains to the bottom of the oil separator and is drawn off from time to time. The cooled and relatively oil-free gas now passes from the oil separator 33 through a pipe 36 to a second oil separator unit 37. In this separating unit I preferably position removable screens of fine mesh wire. Between these screens is neatly fitted a filtering material such as canton fiannel bags. These bags act as an additional oil filter. Between the screens may also be placed fiake asbestos or any other suitable material which will act as an additional filtering medium. The gas passes through the screening units in series so that it is thoroughly cleaned of such oil as may have remained in it, and is delivered through the pipe 38 as perfectly clean dry gas, so that a clean ice may result. From the oil separator 37 the gas passes through the pipe 38 into a condenser 39. Here the gas is liquefied in the usual manner, from which it passes into a liquid receiver 40. The liquid in the receiver 40 of course is condenser pressure is then forced from the receiver 40 through a pipe 41 to a point 42 in the line from which a portion of it passes through a pipe 43 through the liquid cooler 26. The cool liquid leaves the cooling unit 26 through a pipe 45 to a junction 46 in the line from which it passes through pipe 47 to the second stage cooling unit 17. At the junction point 42 in the pipe line 41 a portion of the fluid passes to an expansion valve 48. This valve-may be the ordinary hand operated expansion valve or a no freeze back valve such as that shown in sectional detail in Figure 2. The liquid led through the expansion valve evaporates in the shell in contact with the pipes 44 within the shell containing the liquid from the condenser. The cold expanded fluid from the shell passes out through pipe 54, valve 62 and pipe 56 and through a pipe 25 where it passes through the mixing unit 24 to the suction of a third stage compressor as previously stated.

It will be seen therefore that this stage of liquid cooling is accomplished at the pressure existing at the third stage compressor suction inlet-and the liquidin the tubes is cooled to approximately the evaporating temperature within the shell. Thus, this stage of the liquid cooling is performed at high suction pressure and at goodeconomyu From the junction 46in the pipe: 45 a certain por-- tion of the liquid already cooled in the'fi'rst stage cooler 26 is drawn oil through a pipe 47 and valve 57 and passes through a coil within the second stage liquid cooler 17 from which it passes through valve 73 to a pipe 52 through which it passes to the snow machine. From the junction 46 a portion of the liquid already cooled in the first stage r cooler 26 is drawn oil through a pipe 49 and expanded through an expansion valve 50, or preferably a non-freeze-back valve. One form of such expansion valve is shown in Figure 2. Suction gas to the compressor is: drawn through pipe 18. when the temperature of the gas reaches a predetermined point the thermostat 60 expands, depressing valve stem 61 to open valve 62 against the tension of adjustable spring 63 to permit fluid to expand from pipe 45 through or about coils in the cooler 17. This cold expanded fluid passes around the coils in the shell 17, out through pipe 58, valve 51, pipe 59, through pipe 18, to mixing unit 16, which is in the suction line of the second stage compressor. The valve 51 controlling line 59 must be throttled if necessary to maintain sufiicient pressure in the second stage cooler 17 to prevent the formation of snow thereinthat is, to prevent expansion of the liquid which would form solidified carbon dioxide. From the second stage cooling just described the carbon dioxide in pipe 52 passes to the snow machine where it is expanded to form solid carbon dioxide.- Any gas which is generated in further cooling the cold liquid from its temperature and pressure to the temperatureand pressure of snow, is drawn ofi through a pipe 31, passing through the heat exchange unit,28 to the suction of the first stage compressor. The liquid coolers 17 and 26 are provided with blow-off connections 53 and 54 in order that high pressure gas may be applied to both the tubes and the shells.

This blow-oil system of apparatus operates as follows: i a In, order to blow high pressure gas through the cooler shells 26 and 17 valves 61, 74, 62, 51, 67,

v0 and 76 are closed. Valves 60, 63, v5, 66 and r 69 are open. High pressure fluid from the pipe under very high pressuref The liquid at the 38 may then pass through pipe 53, valve 63, through the shell 26 surrounding the coils 44, through the valve and the pipe 72 to the ax haust. Fluid may likewise pass through a branch of the pipe 53 past the valve 66, through pipe 58 into the shell surrounding the coils in the cooler 17 and out through the valve 69 to the exhaust line 72. This will blow out the shells of the coolers 26 and 17. 4

In order to blow out the coils in these coolers, valves 61,63, 64, 65, 75, 51, 68, 73 and 69 are closed. Valves 60, 74, 70,66, 67 and 76 are open. Pressure fluid passes, from the pipe 38 through pipe 53 and valve 74 into the coil 44 within the cooler 26 and out through valve 70 to the exhaust line 72. Fluid likewise passes throughthe branch of the line 53 past the valve 66, valve 67 and out through valve 76- to the exhaust line 72. This delivers pressure fluid through the coil within the coolers to blow out these coils.

It will be obvious to those skilled in the art that various changes may be made in my device without departing from the spirit of the invention, and I, therefore, do not limit myself to what is shown in the drawing and described in the specification, but only as set forth in the appended claims.

Having thus fully described my said invention, what I claim as new and desire to secure by Letters Patent, is:-- ,1

' 1. A pre-compressingand cooling system for a snow making system comprising a series of com- 'pressors having coolers arranged therebetween in series, a liquid filtering system in said series, a condenser, a plurality of liquid coolers, means for mixing a portion of high pressure, low temperature fluid with the suction gases to the compre'ssors, whereby a low temperature gas is de-v livered to the compressor stages, substantially as set forth. I

2. In a snow making system, first, second and third'stage compressor units, a cooling unit and a mixing chamber between the first and' second, and the second and third compressor units, a condenser, a liquid cooler, means for expanding a portion of the compressed fluid in said cooler to cool the remaining fluid .in it, means for conducting the expanded fiuid to the mixing chamber between the second and third compressor units I where it mixes with and cools the fluid entering the third stage compressor, a second liquid cooler, means for expanding a portion of the cold fluid from the first liquid cooler in the second cooler to cool the remaining fluid in said second liquid cooler, and means for conducting said expanded of compressorswith intercoolers between them, a 1

mixing chamber between adjacent compressors, a condenser, a receiver and a plurality of liquid coolers, means for expanding carbon dioxide from the said receiver to cool the liquid in the first cooler while maintaining the liquid of this cooler at substantially the pressure existing in the receiver, means for expanding a portion of the 14.5 fluid from the first cooler to cool the fluid in a second cooler whilarnaintaining the pressure in the second cooler at substantially that existing in the first cooler, and means for conducting the expanded fluid to mixing chamaeaaaaa bers between adjacent compressors for 1-1;". 5 it with the gas passing to the intake of one co pressor to cool the gas therein and to raise its pressure, substantially as set forth.

4;. In a snow making system having a plurality of compressors and coolers operating in series, a mixing chamber positioned between adjacent compressors, a condenser, a liquid cooler, a snow making chamber, means for drawing gas from the snow making chamber and expanding it in heat exchange relation with the gas in the mixing chamber, and means for expanding high pressure liquid about said liquid coolers to cool the liquid therein, substantially as set forth.

5. The method of making carbon dioxide ice which consists in compressing carbon dioxide through a series of stages, cooling the gas between each of the compressing stages and mixing cold gas therewith, condensing the gas after passing through the last compressing stage, expanding a portion of the liquid to cool the remainder while keeping the remainder under approximately the same pressure, expanding the cold liquid to a snow machine and conducting all gaseous carbon dioxide from the snow machine and introducing it into gaseous carbon dioxide prior to the entry of said gas into the first compression stage, substantially as set forth.

6. A snow making system having a plurality of compressor units with coolers between them, a condenser, a receiver, a liquid cooler, means for expanding a portion of the cooled liquid to i'ur= ther cool the remaining portion of liquid in the liquid cooler, means for main Hr: the liquid in the cooler under substantially the same high pressure at which it leaves the liquid receiver while undergoing cooling, means for conducting cold liquid from the liquid cooler to a snow q; t chine, and means for returning gaseous carbon dioxide generated by expansion in the snow machine and mixing it with the carbon dioxide entering the first compressors, substantially as set forth.

7. In a snow king system, a series of com-=- pressors having cooling units between them, a condenser, a plurality of liquid coolers, means for expanding a portion of the liquid from the re ceiver to cool the remainder of the liquid in the first liquid cooler while mainta the liquid in the cooler at substantially the pressure maintained in the receiver, means for expanding a portion of the liquid from the first liquid cooler to cool the liquid in a second liquid cooler while maintaining the liquid in this cooler at substantially the same pressure as existed in the first liquid cooler, means for conducting the cold liquid from the second cooler to a snow machine and means for conducting gas expanded in the snow machine and mixing it with gas entering some of the compressors to cool said gas, substantially as set forth. 

